Originální popis anglicky:
fmtmsg - display a message in the specified format on standard error and/or a
system console
Návod, kniha: POSIX Programmer's Manual
#include <fmtmsg.h>
int fmtmsg(long
classification, const char
*label, int
severity ,
const char *
text, const char
*action, const char
*tag );
The
fmtmsg() function shall display messages in a specified format
instead of the traditional
printf() function.
Based on a message's classification component,
fmtmsg() shall write a
formatted message either to standard error, to the console, or to both.
A formatted message consists of up to five components as defined below. The
component
classification is not part of a message displayed to the
user, but defines the source of the message and directs the display of the
formatted message.
- classification
- Contains the sum of identifying values constructed from the
constants defined below. Any one identifier from a subclass may be used in
combination with a single identifier from a different subclass. Two or
more identifiers from the same subclass should not be used together, with
the exception of identifiers from the display subclass. (Both display
subclass identifiers may be used so that messages can be displayed to both
standard error and the system console.)
- Major Classifications
Identifies the source of the condition. Identifiers are: MM_HARD (hardware),
MM_SOFT (software), and MM_FIRM (firmware).
- Message Source Subclassifications
Identifies the type of software in which the problem is detected. Identifiers
are: MM_APPL (application), MM_UTIL (utility), and MM_OPSYS (operating
system).
- Display Subclassifications
Indicates where the message is to be displayed. Identifiers are: MM_PRINT to
display the message on the standard error stream, MM_CONSOLE to display the
message on the system console. One or both identifiers may be used.
- Status Subclassifications
Indicates whether the application can recover from the condition. Identifiers
are: MM_RECOVER (recoverable) and MM_NRECOV (non-recoverable).
An additional identifier, MM_NULLMC, indicates that no classification component
is supplied for the message.
- label
- Identifies the source of the message. The format is two
fields separated by a colon. The first field is up to 10 bytes, the second
is up to 14 bytes.
- severity
- Indicates the seriousness of the condition. Identifiers for
the levels of severity are:
- MM_HALT
Indicates that the application has encountered
a severe fault and is halting. Produces the string "HALT"
.
- MM_ERROR
Indicates that the application has detected a
fault. Produces the string "ERROR" .
- MM_WARNING
Indicates a condition that is out of the
ordinary, that might be a problem, and should be watched. Produces the string
"WARNING" .
- MM_INFO
Provides information about a condition that is
not in error. Produces the string "INFO" .
- MM_NOSEV
Indicates that no severity level is supplied
for the message.
- text
- Describes the error condition that produced the message.
The character string is not limited to a specific size. If the character
string is empty, then the text produced is unspecified.
- action
- Describes the first step to be taken in the error-recovery
process. The fmtmsg() function precedes the action string with the
prefix: "TO FIX:" . The action string is not
limited to a specific size.
- tag
- An identifier that references on-line documentation for the
message. Suggested usage is that tag includes the label and
a unique identifying number. A sample tag is
"XSI:cat:146" .
The
MSGVERB environment variable (for message verbosity) shall determine
for
fmtmsg() which message components it is to select when writing
messages to standard error. The value of
MSGVERB shall be a
colon-separated list of optional keywords. Valid keywords are:
label,
severity,
text,
action, and
tag. If
MSGVERB
contains a keyword for a component and the component's value is not the
component's null value,
fmtmsg() shall include that component in the
message when writing the message to standard error. If
MSGVERB does not
include a keyword for a message component, that component shall not be
included in the display of the message. The keywords may appear in any order.
If
MSGVERB is not defined, if its value is the null string, if its
value is not of the correct format, or if it contains keywords other than the
valid ones listed above,
fmtmsg() shall select all components.
MSGVERB shall determine which components are selected for display to
standard error. All message components shall be included in console messages.
The
fmtmsg() function shall return one of the following values:
- MM_OK
- The function succeeded.
- MM_NOTOK
- The function failed completely.
- MM_NOMSG
- The function was unable to generate a message on standard
error, but otherwise succeeded.
- MM_NOCON
- The function was unable to generate a console message, but
otherwise succeeded.
None.
The following sections are informative.
- 1.
- The following example of fmtmsg():
fmtmsg(MM_PRINT, "XSI:cat", MM_ERROR, "illegal option",
"refer to cat in user's reference manual", "XSI:cat:001")
produces a complete message in the specified message format:
XSI:cat: ERROR: illegal option
TO FIX: refer to cat in user's reference manual XSI:cat:001
- 2.
- When the environment variable MSGVERB is set as
follows:
MSGVERB=severity:text:action
and Example 1 is used,
fmtmsg() produces:
ERROR: illegal option
TO FIX: refer to cat in user's reference manual
One or more message components may be systematically omitted from messages
generated by an application by using the null value of the argument for that
component.
None.
None.
printf() , the Base Definitions volume of
IEEE Std 1003.1-2001,
<fmtmsg.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html
.
